The Effectiveness of Home Water Purification Systems on the Amount of Fluoride in Drinking Water.

Statement of the Problem Water purification systems for domestic use have drawn significant attention over the past few years. This can be related to the improvement of public health and concern for water contamination. Purpose The aim of this study was to evaluate whether home water purification systems eliminate the essential materials such as fluoride besides filtrating the heavy ions and other unwanted particles out of water. Materials and Method In this experimental study, six most frequently used commercial brands of water purifiers were evaluated and compared. Specimens were collected right before and after setting up the device, and 6 months later. Then, spectrophotometry (the Harrison device) was performed to compare fluoride clearance by each home water cleaner device. Results Based on the data collected from all water purification devices in different locations, the amount of fluoride was significantly different before and right after using home water purifier and six months later (p= 0.001 and p= 0.00, respectively). Conclusion The filtration of water significantly decreased its fluoride concentration. The fluoride content of purified water was approximately as much as zero in some cases.


Introduction
Fluoride is a natural element branched from Fluorine. This element can be found in all sorts of water and soil. Out of every kilogram of outer layer of earth, 0.3 gram is fluoride. Mineral waters have more amount of this element compared to other sources. [1] About 60 years ago, Grand Rapids in Michigan State was the first city in which fluoride supplement was synthetically added to tap water. In US, adding fluoride to community water supplies of many cities has improved the oral health of millions of American citizens. [2] Fluoridation of community water supplies is adding a specific amount of fluoride (0.7-1.2 ppm) to water in order to reduce the risk of dental caries. By 2002, almost 170 million Americans were provided with this privilege. [3] Since most of the systemic fluoride is provided through tap water to population, many policies have been established to add fluoride to community water regarding its benefits for teeth and bones. [4] In regions and countries that do not have waterfluoridation technology, there are natural supplements as previously mentioned. For example, Iran has many mineral water supplies that contain considerable amounts of fluoride. Amount of fluoride in natural mineral waters depends on weather conditions; the warmer the weather is, the higher the amount of fluoride can be detected. Mineral waters in southern regions that have warmer weather contain more fluoride.
In Iran, the highest amount of fluoride has been found in southeast and northeast areas.
Water purification systems for domestic use have drawn much of attention over the past few years. This can be related to improvement of public health and concerns for water contamination. There are several types of home water purification systems that can be categorized into 3 different groups [5] as filtered systems, systems using UV irradiation, and ion-exchange systems.
The aim of this study was to find out whether domestic water purification systems could eliminate the essential materials such as fluoride besides filtrating the heavy ions and other unwanted particles out of water.

Materials and Method
In this study, 6 frequently used commercial brands of water purifiers in Ahwaz were compared. The commercial brands evaluated in the current study were Latin alphabetic words were used to code each commercial device. Numbers were used for samples obtained before and after setting the device. [6] The results were analyzed by using paired sample t-test, with alpha (ɑ) set at 0.05.

Results
The amount of fluoride in water before and after using six brands of water purifier device is summarized in Table 1.
Based on the data gathered from all water purification devices set in different regions, the level of flu-  oride was significantly different before and after using home water purifier (p= 0.001). It was found that home water purifiers nearly eliminated fluoride from tap water. Table 2 represents the results of t-test.
Another round of sampling was done 6 months later from the same filters of home water purifier. Details are illustrated in Table 3 and 4. Clasen et al. [5] in their study reported that 3 different home purification systems ,the ceramic candle gravity filter, iodine resin gravity filter, and iodine resin faucet filter, reduced bacterial contamination by four logs and decreased ions such as fluoride and arsenic, as well.

Discussion
Moreover, there are certain methods to reduce the excessive amount of fluoride in the water. One of the best-known methods is absorption technique. [7] Evaluation of 6 different commercial water purifiers has not been done in any other study; therefore, there is no similar study to compare the results exactly.  More evaluations are suggested to be performed on home water purification systems, and more strategies should be devised to preserve the essential elements of tap water.

Conclusion
The current study found considerable differences between the amount of fluoride before and after filtration with home purification device; that is filtration significantly decreased the fluoride concentration even as much as 100% in some cases.

Conflict of Interest
None declared